Spelunker does support up to four players locally and six players online. The multiplayer is refreshingly funny — seeing your friends dying because of their jumps seems cruel, but is still fun nonetheless. The entire game can be played cooperatively too. Playing it online will give way to alot of high scores and allow you to see people who are really good at the game. Other than the traditional mode, once can also engage in cave racing, where players have to reach the bottom faster then their opponents. There is also a different course features that will leave players racing for bombs and flares as there is only a limited number on each level. The drawback to playing this way is that each person gets their own split-screen on a television set, so the view is often divided into four. This gives you the ability to see where your teammates or opponents are at all times, but doesn't provide the whole view of the area which would be useful.
Spelunker HD is a game that is very much rooted into its 8-bit ancestor. It is an amazing game, difficult, but amazing even 30 years later. The updated graphics as well as new multiplayer modes and capabilities add a good touch to the game. The frustration only leads to the appeal of it for old school gamers. New school gamers will find it very frustrating all the time and might not give the game the chance that it deserves.
Spelunker HD is rated E (Everyone) by the ESRB for Comic Mischief.