If the timing belt or chain breaks or jumps time, this can cause the engine to stop running or run very badly. So if you have a no-start condition and you know you have spark and fuel, the next thing to check might be the mechanical timing of the engine. You can usually do this by removing a cover or inspection plate. One other quick check is to remove the distributor cap (if equipped) and crank the engine. If the rotor does not spin when you do this, you likely have a broken timing belt or chain. If the engine is out of time or breaks a belt, repair it, then recheck for your no-start issue.
You might be concerned that engine damage was done if you jumped time, and you'd be right to have that concern, but the truth is, no matter what, you're going to have to fix the timing first. When I'm confronted with this issue, I often replace the broken belt or chain and try to start the engine. If I have a compression loss at that point due to bent valves, then I start digging into removing the cylinder head. If the engine runs, I call it a win and move on.
My point here is don't worry about bent valves until you know you have them. You won't know you have bent valves until you have everything back in time and you try to start the engine. This brings us to our next topic: no compression.