D&D: Chronicles of Mystara: GGPO Netcode, quality bonus features, and starring a license that I'm sure cost them some extra money to secure. I'm beyond glad to finally have these games available to play legitimately!
The games longevity shouldn't be tied to the achievements anywho, but what the actual games offer. Tower of Doom offers branching paths. Mystara offers that, in addition to multiple endings per character, and characters that play, and can be played differently. Even the "press start" alt looks for the characters can come with unique equip / spell load outs.
Gotta love the unlockables for the Vault too. Too many classic releases miss the extra touch of honoring the art and history of these classics. While these are purely cosmetic, they're not the kind of things you get in many quick & dirty ports.
Then you have the unlockable "House Rules" settings, which also do a great job at mutating the game to play differently. Basically a "make your own bonus mode" setting list, allowing you to change the game into time attack, survival, or a variety of other modes. A nice way to bring something fresh to games that otherwise aren't going to get additional characters/stages/etc. It's a pretty solid way to add replay value, and I really wish more modern games would offer an extra so well thought-out.
Much like M2's classic releases, this one is several cuts above the "cash-in" ports we saw earlier in this generation. And it's of 2 games many would think out of reach forever, neither of which have ever seen a non-Japanese console release.
Oh, and I suggest that people actually read the "How to Play" and title-screen info ticker, too, especially with Mystara. There's a LOT of obscure, hard-to-pick-up-on details that could fly right over ones head, even after playing. I love how the Thief actually has steal and Back-attack abilities, and the fact that the Dwarf can actually salvage additional money from breaking down treasure chest.
I always love how old Arcade ports (especially of fantastic games) always feel like I instantly get my money's worth. Especially compared to the quarters I'd have spend clearing them in arcades, even before .50 / .75+ cent per play. I'm blessed with a local Co-Op partner as well, so I've been able to finally get SO many classic this gen, probably for collectively less than I spend on them across 1 summer between multiple arcades...
I guess games like this might be an acquired taste, but if one has such taste, boy do they hit the spot. I ran through the 1 stage of the Mystara demo SO MANY TIMES last night, trying to get used to some of the advanced strategies and tactics, per-character, that playing Tower of Doom in arcades gave me absolutely no clue towards. Such a great year for Beat 'em-Ups!