Spot the Error

[Deathbringer]

You can either use a tile viewer like Tile Molester, GDD, TiledGGD, or yy-chr (this one is what I used for the game). Sometimes you get lucky and a game has uncompressed stuff (in Spidey's case, it looks like all the enemies and bosses can be taken straight out of the ROM itself) but most of the time a game will be compressed.