Spelunky has 2 Chrome Web Store editions, one of which is called "Spelunky HTML5 Edition" This is an outdated version of Spelunky Classic, and while it has many bugs, the most notable is the 0.5 jump bug. The player will only be able to jump 0.5 tiles, and can, however sprint and ledge climb 1 block. The bug will occur every time the game is launched, and will only happen once until the game is closed and re-opened. The following will end the glitch and causes a reaction from the item.
Collecting a treasure will pick it up multiple times until the glitch ends. Doing this should give you about 1000% of the treasure's value.
Crates can be opened many times, usually giving all but one of: a parachute, climbing gloves, a pitchers mitt, a cape, a compass, sticky bombs, spring shoes and spike shoes. You will usually get 70-80 (sticky bombs) and 45-70 ropes and a shotgun. It is also possible to get a teleporter and jetpack, but that takes luck.
Aggravating a giant spider will spawn about 50-70 angry giant spiders, typically not done on purpose, but the gems the spiders drop give over $200000 and tons of bomb paste. The spiders can be dispatched with a single whiplash.
Detonating a bomb will cause the bomb to explode repeatedly and fly around unpredictably until the glitch randomly ends. Fun, but not helpful.
If you manage to make it to a store, you can simply walk out with the shopkeeper's items without him attacking you.
Having a push block fall will end the bug with no adverse reactions.
Pots cannot be broken, unless they are whipped. Whipping a pot will end the glitch with no reactions.
All of these fixes cause adverse amount of lag.
While the glitch is active, arrow traps will not stun you. This does not end the glitch, though.
When the glitch is active, the first map you load will be from a list of seeds. This means closing and reopening the game multiple times should give you the same map.
Other bugs include:
It is impossible to set off arrow traps with ropes if they are thrown downwards.
Killing a large enemy (mummy, yeti king) with a bomb will crash the game.
Sticky bombs sometimes follow the movements of the closest enemy, even if they are thrown at a surface. (For example, a bomb thrown at a wall may act like it is attached to a monkey behind it.)
Killing two enemies at once will occasionally cause a major glitch. When any other enemy appears on the screen, blood will appear as if they died, but they will remain alive. The game will crash after around 30 seconds.
You can die by jumping into push blocks at the wrong angle.