The first Eufloria was one of the earliest games I picked up on Steam, so I have fond memories of it. It's sort of like an RTS stripped down to the very essentials; in the first game there are just two different kinds of units (and one of them comes in very limited quantities), so there's less "rock-paper-scissors" jockeying and more timing and exploiting openings. (Maybe two enemy factions have a big battle, and you show up to mop up the survivors and take over.) The beautiful floral artstyle and relaxing music was also a big draw. It can certainly be difficult depending on the level, but much of the time it's a great relaxation game.