Starbase is a complex space colonising sandbox game.
It has FPS weapons (think of Planetside 2), complex building with a built-in ship designer (Kerbal Space Program), built-in scripting language (severely limited so that you can't fully automate mining or auto-turrets efficiently), proper space dogfighting (e.g. Star Citizen, NO point and click like EVE or Dual Universe), voxel damage model (simply put, everything you build can be destroyed, crushed, your ship can be cut in half with a laser and also repaired should you choose to do so), it's an MMO with everything that comes with it, it's one big cluster (no instances except for landing pads and the ship designer) with thousands of players online, factions, resource gathering and crafting, global marketplace, base building,...
System requirements are decent. You can trust the system requirements on Starbase's Steam page. It's quite playable with minimal specs, but better PC is recommended for crowded areas, especially mass PVP. Visuals are good enough, not an AAA level, but definitely not bad.
Starbase can be a truly unique experience some day, but right now is so far from complete that I can't recomment buying an early access unless you only want to support developers without playing the game. There is no part of the game that is complete, releasing early access with a LIVE (no wipe) server right now was a big mistake from my point of view, there is barely enough working content and player base dropped to low hundreds soon after release because of that.