Not just one, but two PC-bound Sonic games were announced at a 25th anniversary event today; truly, these are magical times. Sonic Mania is being developed by a lot of people (SEGA, Christian Whitehead, Headcannon, and PagodaWest Games) and is a 2D retro-classic-leaning platformer.
Project Sonic 2017 meanwhile is presumably operating under a working title, and is harder to classify because the trailer doesn’t really feature any gameplay. The teaser is implying it’s akin to a Sonic Generations sequel, so let’s go with that for now.
The former has a rough release window of ‘Spring 2017’, while the latter is shooting for ‘Holiday 2017’ (so probably November-ish, unless it slips). Here are both trailers.