The dataset viewer is not available for this split.
Error code: StreamingRowsError
Exception: CastError
Message: Couldn't cast
shard: string
action_space_version: int64
art_version: int64
episodes: int64
frames: int64
steps: int64
bytes: int64
bytes_per_frame: double
reward_total: double
goal_episodes: struct<0: int64, 1: int64, 2: int64, 3: int64>
child 0, 0: int64
child 1, 1: int64
child 2, 2: int64
child 3, 3: int64
goal_frames: struct<0: int64, 1: int64, 2: int64, 3: int64>
child 0, 0: int64
child 1, 1: int64
child 2, 2: int64
child 3, 3: int64
goal_success: struct<0: double, 1: double, 2: double, 3: double>
child 0, 0: double
child 1, 1: double
child 2, 2: double
child 3, 3: double
policy_counts: struct<scripted: int64, scripted_eps0.2: int64, scripted_eps0.5: int64, random: int64, explorer: int (... 3 chars omitted)
child 0, scripted: int64
child 1, scripted_eps0.2: int64
child 2, scripted_eps0.5: int64
child 3, random: int64
child 4, explorer: int64
seconds: double
task_frame_share: struct<0: double, 1: double, 2: double, 3: double>
child 0, 0: double
child 1, 1: double
child 2, 2: double
child 3, 3: double
gb: double
task_episode_share: struct<0: double, 1: double, 2: double, 3: double>
child 0, 0: double
child 1, 1: double
child 2, 2: double
child 3, 3: double
shards: int64
to
{'shards': Value('int64'), 'episodes': Value('int64'), 'frames': Value('int64'), 'bytes': Value('int64'), 'gb': Value('float64'), 'bytes_per_frame': Value('float64'), 'task_episode_share': {'0': Value('float64'), '1': Value('float64'), '2': Value('float64'), '3': Value('float64')}, 'task_frame_share': {'0': Value('float64'), '1': Value('float64'), '2': Value('float64'), '3': Value('float64')}}
because column names don't match
Traceback: Traceback (most recent call last):
File "/src/services/worker/src/worker/utils.py", line 147, in get_rows_or_raise
return get_rows(
dataset=dataset,
...<4 lines>...
column_names=column_names,
)
File "/src/libs/libcommon/src/libcommon/utils.py", line 272, in decorator
return func(*args, **kwargs)
File "/src/services/worker/src/worker/utils.py", line 127, in get_rows
rows_plus_one = list(itertools.islice(safe_iter(ds, dataset=dataset), rows_max_number + 1))
File "/src/services/worker/src/worker/utils.py", line 483, in safe_iter
yield from ds.decode(False) if ds.features else ds
File "/usr/local/lib/python3.14/site-packages/datasets/iterable_dataset.py", line 2840, in __iter__
for key, example in ex_iterable:
^^^^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/iterable_dataset.py", line 2373, in __iter__
for key, pa_table in self._iter_arrow():
~~~~~~~~~~~~~~~~^^
File "/usr/local/lib/python3.14/site-packages/datasets/iterable_dataset.py", line 2398, in _iter_arrow
for key, pa_table in self.ex_iterable._iter_arrow():
~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
File "/usr/local/lib/python3.14/site-packages/datasets/iterable_dataset.py", line 536, in _iter_arrow
for key, pa_table in iterator:
^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/iterable_dataset.py", line 419, in _iter_arrow
for key, pa_table in self.generate_tables_fn(**gen_kwags):
~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/packaged_modules/json/json.py", line 343, in _generate_tables
self._cast_table(pa_table, json_field_paths=json_field_paths),
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.14/site-packages/datasets/packaged_modules/json/json.py", line 132, in _cast_table
pa_table = table_cast(pa_table, self.info.features.arrow_schema)
File "/usr/local/lib/python3.14/site-packages/datasets/table.py", line 2378, in table_cast
return cast_table_to_schema(table, schema)
File "/usr/local/lib/python3.14/site-packages/datasets/table.py", line 2306, in cast_table_to_schema
raise CastError(
...<3 lines>...
)
datasets.table.CastError: Couldn't cast
shard: string
action_space_version: int64
art_version: int64
episodes: int64
frames: int64
steps: int64
bytes: int64
bytes_per_frame: double
reward_total: double
goal_episodes: struct<0: int64, 1: int64, 2: int64, 3: int64>
child 0, 0: int64
child 1, 1: int64
child 2, 2: int64
child 3, 3: int64
goal_frames: struct<0: int64, 1: int64, 2: int64, 3: int64>
child 0, 0: int64
child 1, 1: int64
child 2, 2: int64
child 3, 3: int64
goal_success: struct<0: double, 1: double, 2: double, 3: double>
child 0, 0: double
child 1, 1: double
child 2, 2: double
child 3, 3: double
policy_counts: struct<scripted: int64, scripted_eps0.2: int64, scripted_eps0.5: int64, random: int64, explorer: int (... 3 chars omitted)
child 0, scripted: int64
child 1, scripted_eps0.2: int64
child 2, scripted_eps0.5: int64
child 3, random: int64
child 4, explorer: int64
seconds: double
task_frame_share: struct<0: double, 1: double, 2: double, 3: double>
child 0, 0: double
child 1, 1: double
child 2, 2: double
child 3, 3: double
gb: double
task_episode_share: struct<0: double, 1: double, 2: double, 3: double>
child 0, 0: double
child 1, 1: double
child 2, 2: double
child 3, 3: double
shards: int64
to
{'shards': Value('int64'), 'episodes': Value('int64'), 'frames': Value('int64'), 'bytes': Value('int64'), 'gb': Value('float64'), 'bytes_per_frame': Value('float64'), 'task_episode_share': {'0': Value('float64'), '1': Value('float64'), '2': Value('float64'), '3': Value('float64')}, 'task_frame_share': {'0': Value('float64'), '1': Value('float64'), '2': Value('float64'), '3': Value('float64')}}
because column names don't matchNeed help to make the dataset viewer work? Make sure to review how to configure the dataset viewer, and open a discussion for direct support.
Small Worlds: a generated pixel-platformer corpus
2,025,385 frames of a single controllable agent in a deterministic 2D platformer, with per-frame actions, rewards, episode boundaries and task labels. Nothing here was scraped: every frame was rendered by a simulator written for the purpose, which makes the coverage structure a controlled variable.
Built for research on world models and on hallucination in generative dynamics models. Accompanying report: Small Worlds: Subject-Scale Failure in Reconstruction-Trained World-Model Tokenizers.
Why this corpus exists
Two properties are hard to obtain from recorded gameplay and are exact here:
- A known finite palette. The renderer emits exactly 21 colours, so reconstruction can be scored as exact per-pixel agreement and restricted to any semantic subset — the agent's own colours, for instance. This is what makes the paper's central measurement possible.
- Coverage as a dial. Each episode targets one coin drawn from a skewed distribution and ends when it is collected, so a goal is a task and the uppermost platform is visited in ~3% of episodes by construction.
The agent occupies a measured 1.30% of frame pixels.
Splits
| split | episodes | frames | size | purpose |
|---|---|---|---|---|
train |
35,000 | 2,025,385 | 0.75 GB | training |
val |
2,400 | 136,620 | 0.05 GB | evaluation |
test |
2,400 | 139,157 | 0.05 GB | held out entirely |
probe_ledge |
2,400 | 364,684 | 0.13 GB | 100% low-coverage region |
Seed blocks are widely separated and verified disjoint.
Format
One .npz per shard, with a .json of per-shard statistics beside it.
| field | shape | dtype | notes |
|---|---|---|---|
frames |
(N, 128, 128, 3) | uint8 | native resolution, no resampling |
actions |
(N,) | uint8 | 0–5; 255 marks a terminal step |
action_vecs |
(N, 16) | float32 | zero-padded continuous encoding |
action_mask |
(16,) | float32 | 3 valid dimensions |
rewards |
(N,) | float32 | coin +1, crate +2, door +5 |
ep_id |
(N,) | int32 | episode boundaries |
goal |
(N,) | uint8 | task label; enables per-task resampling |
terminal |
(N,) | bool |
Frames are stored once per episode; frames[i+1] is the successor within an
episode and ep_id marks boundaries. Flat pixel art deflates well — 368
bytes/frame against 49,152 raw.
import numpy as np
from huggingface_hub import hf_hub_download
p = hf_hub_download("maxmill/small-worlds-pixel-platformer", "train/shard_0000.npz", repo_type="dataset")
d = np.load(p)
frames, actions, rewards = d["frames"], d["action_vecs"], d["rewards"]
Coverage structure
Episode share and frame share are deliberately mismatched, reproducing the heavy-tailed structure of larger corpora:
| task | episode share | frame share | ratio |
|---|---|---|---|
| ground | 31.9% | 5.3% | 0.17 |
| P1 | 31.1% | 37.5% | 1.21 |
| P2 | 31.0% | 41.6% | 1.34 |
| P3 (rare) | 6.0% | 15.5% | 2.57 |
Behaviour policies
| policy | share |
|---|---|
| scripted (routes over a physics-derived hop graph) | 40% |
| scripted + 20% random | 25% |
| scripted + 50% random | 15% |
| uniform random | 15% |
| explorer (biased to the rare platform) | 5% |
Measured properties
- Redundancy: 25.4% of frames unique (mean 3.94 repeats) → ~515k distinct frames
- Intrinsic dimensionality: a frame is a deterministic function of ~26 bits of state
- Palette: exactly 21 colours; 9 belong to the agent
- Versioning: every shard carries
action_space_versionandart_version
Licence
MIT.
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