Beat the game a few hours after my last post. Pretty good quality rom, good graphics, music. Gameplay mechanics, puzzles, and difficulty scaling are solid. Good job! Decided to do another more thorough playthrough/bug test since I ran into a few more in later levels:
-World 1-3
Ending the level your bot moves off to the left instead of up/out the exit.
-World 1-8
3 horizontal solid tiles on the surface level just above the exit arrow can be drilled down through when they shouldn't be.
-World 2-1
When refueling from the depot from below and completing the level, when you play the level again and try to refuel from above, the depot moves you down instead of pushing you back up, getting you stuck and potentially forcing a destruct/restart. This one seems to be hit/miss on replication.
-World 2-3
On the surface, along the horizontal row of solid tiles just below the fuel depot/exit, the last two tiles to the right can be drilled down through. Both get you stuck on rocks below, the right most you can drill back up, but the one to the left of it gets you stuck, forcing a destruct/restart.
-World 2-9
The 5 electro-plating tiles starting from the power shed on the surface can be drilled through getting players stuck on a rock below. The hard tile on the surface just above the two pits on the left can be drilled through getting players stuck on a rock below. The pits on the left when filled can be drilled through, getting players stuck on the floor below. The 3 hard tiles on the surface at the bottom, above the mineral deposit can be drilled through. In most instances the player can however drill back up from the below to safety, if they have the fuel.
-World 2-11
Self destructing on the surface warps you to the left side of the map.
-World 2-12
Collecting the crystal doesn't show up on the level map.
-World 3-1
Walking into the power shed the players character is the mech instead of the pilot sprite.
-World 3-3
On the lower level on the space just above the pit on the far left, you can drill up into a rock formation and get stuck until you drill down.
-World 3-12
Multiple solid tiles around the surface volcano in the upper left can be drilled up/down through, putting the player out of bounds/ getting stuck.
=>Recursive Level Select Bug<=
After entering/level selecting 8 times, when leaving a level with level select and entering another level, open the main menu, it will warp you to the level you left. If you self destruct, you'll be moved to that world/level and come out from it on the level map. If you instead go to level select directly you'll come out the recently selected map on the world/level map. This seems to remain persistent across all worlds/levels when it occurs, with the map you selected potentially having more minerals than the bugged map you get warped to, the ore requirements persist, and the player, movable blocks and obsticals are displaced or added and don't work right, so you'll have to self destruct/leave the level and restart. In instances I couldn't play world 1-12 as it would spawn in world 1-11, same with 2-4 spawning 2-3, and after re-routing the power in 2-4 and going out the building, it would warp to 2-3, breaking the game. Rebooting it fixes the issue.
-One instance in world 2-12 also had the mech suit disappear when exiting it until you self destruct. Could be related to level select bug.
P.S. Managed to get PAR on most levels, and high scores on others. Can't tell whether its always achievable, but is good fun. ;)