First post, by SideLiner
SideLine is a shoot 'em up made by a Taiwanese group for MS-DOS that went virtually unknown and was only rediscovered in recent years. Thanks to various efforts in unearthing it (see here: shmups.system11.org/viewtopic.php?f=1&t=3209), the game's producer actually gave his blessing for it to be released as freeware:
This is seriously the best shoot 'em up ever made for MS-DOS. It's got full multiplayer, and feels like a relatively modern arcade game for the time it was released, with none of the pitfalls like inertia on movement or gigantic hitboxes with lifebars like the commonly known shoot 'em ups that dominated MS-DOS gaming at the time (Tyrian 2000 and Raptor). It's important to emphasize just how good the game is and how unfortunate it was it essentially went completely unknown for decades, because it's essentially the pinnacle of shoot 'em ups for MS-DOS and plays exceptionally well, featuring 8 stages, multiple loops, 3 difficulties, a massive variety of weapons, and so on.
If you're looking for a hidden treasure, you owe it to yourself to grab a copy of this and play it.