One of my better-developed ideas, one which started back when I was in high school, is (as the title suggests) an asymmetric science-fiction-themed board game with some card-based elements. I've written up a set of rules and even done a few cards, which I'll get around to posting after some cleaning up, but for now I'd just like to hear some thoughts on the overall idea and mechanics.
The game is themed around "a science fiction movie" - that is, each play-through is a (somewhat corny) science fiction action movie. The game is strongly asymmetric: One player plays as the "Heroes", guiding the actions of a small group of characters aiming to achieve a particular goal; the other plays as the "Director", who is in charge of all other aspects of the scenario, including the setting, the heroes' goal itself, the many mishaps which can take place along their way to reaching it, and the particular "enemy" in that particular scenario. In some ways, it's similar to the tabletop "DM/GM" paradigm, only competitive. If the heroes accomplish their goal, that player wins; if they don't, the Director wins.
The game begins with a setup phase, in which players spend points to "buy" various things. The Director goes first, and can spend as many points as they wish; their total at the end is the number of points available to the Heroes player. At minimum, the Director "buys" a map and a particular goal card out of many available for that map; the harder the map or the goal, the more points it costs.
They also select an enemy from the many available (Stargate-esque von Neumann replicators, a nightmarish psychic entity and an organised alien strike force are three of the options). Each enemy has a "Basic" unit (mooks, represented by the most numerous token), an "Elite" unit (elite mooks, with fewer tokens) and up to four "Special" units (semi-unique cases, very few tokens), allowing diverse play options with the same set of physical tokens. The rules for each enemy vary widely. Some enemies allow the spending of extra points for initial advantages.
The Heroes player uses points to buy Characters (science fiction archetypes, such as "The Scientist" or "The Space Marine"), and Equipment for them to use.
Both players can also buy two types of cards; Plot cards, which affect the entire game, and Drama cards, which are "action"-type cards which are put into a "hand" and played mid-game, and have an immediate or temporary effect.
Once setup is complete, players take turns moving their characters/units (all characters or units get "a move" every turn), and occasionally playing Drama cards, until somebody wins.
Comments and criticisms?
It's definitely combat/tactically-oriented. The precise details of the goal cards will depend on the maps, which I'm having some trouble with (there is a simplified hidden movement mechanic for several enemies which makes line of sight important, which means I'm having some trouble designing balanced maps), but a few broad examples are:
Exterminate: Eliminate the enemy entirely. Leave none alive. (Obviously a quite high-cost card, since under most circumstances the game would be balanced to have the Heroes scrambling to finish their objectives without even a hope of directly combating their opponent(s))
Power Up the Ship: Start up the four generators located around the ship. Any character with the Scientist attribute can spend a full turn to start up a generator while adjacent to it. Until the first two generators are started up, the effect of In The Dark applies. (In The Dark is a Plot card which reduces sight and combat range for all characters)
Escape: The enemy is overwhelmingly strong. Get at least one character to the exit so that they can warn the outside world. (A low-cost goal card, to ensure that the enemy really is overwhelmingly strong compared to the heroes)
The map will definitely be non-abstract. I was originally thinking square grid, but hex is also an option.