This is a good question! The biggest thing about getting anyone involved with any event or sign up or anything where you are asking them for something is what value you’re giving them. A demo is a great way to provide some value on your side, but it’s a huge outset of dev time, especially early on. So what else can you do?

You essentially need to have some kind of lead magnet. There’s a few good articles about what ‘lead magnets’ are and how to use them that are worth reading here. (One) (two) and (three).

However, not every event will make it possible for you to do so - e.g. you might be swamped and not have time to prepare anything, so throwing up a tweet to promote your involvement is maybe all you can do with the time you have.

However, here are some options you could consider:

• Could you promise a future Steam key as a sweepstakes?
  • One way to do this, for example, to be like ‘if you wishlist us during this event and submit a screenshot with the date here, you go into the draw to win a Steam key at launch.’ Simple, effective, can be directed to be for your store page, or a sign up to a mailing list, or social sign up. You could even make it simpler - post in this thread on our discussion board on Steam and you go into the draw. You can do this both on Steam but also on socials and other networks. People love free stuff - even if they already have the free thing, or aren’t even necessarily interested in it. Note that there are quite a few digital sweepstake things to consider here and some legalities you’d want to triple check (e.g. can you encourage wishlisting or sweepstake in Steam directly, as an example), so don’t take the above as gospel, but it is doable!
• Can you run some kind of community event for the duration of the festival?
  • You might not have a community yet, but communities don’t build out of nothing to do. So, why not create opportunities for people to engage with you. Let’s say it’s the Steam City Builder event and you’re a city builder game about skyscrapers. You could ask players to vote on the best skyscraper in the world, and whichever one wins will go into the game. Or, you could ask the to submit their ideas for a new skyscraper building type and the best voted one will win merch, or a Steam key, or any other kind of value add. You get the idea - what is relevant and interesting and doable? You might not have these things on hand right now, but you can promise future value so long as you ensure you deliver on it.
• Can you run a social campaign that’s a bit silly or different with the CTA being the Steam event?
  • Let’s say it’s for the Cooking Fest, can you make some insanely elaborate strange meals relevant to your game daily as suggested by players and post this on socials to point to the store page? Think Roll for Sandwich or similar, and use that to drive traffic. Remove the ‘Steam’ and ‘Demo’ part from your brain entirely - what would be fun or silly content for someone into cooking to see that could potentially lead to interest in the game?
• Can you just simply run advertising?
  • You could spend small on some ads that present your game, or boost your trailer if you have one, and direct straight to Steam. This will let you test different copy too if you’re early in the process, and test different audiences on small spends to see who responds, where, and how.

Ultimately, what works for your game is totally dependent on what the game is and what your goals are. If you’re trying to get visibility in the festival to build wishlists, finding a straightforward lead magnet you can use to direct traffic to Steam AND/OR encourage a wishlisting action is the best thing you can do without a demo, and your Steam community posts should reflect this goal, as well as any social posts you tackle.