The shield not working when you are moving towards the enemy is not intended, but kind off is.
The shield is programmed to slow the enemy down to its startingspeed in a 3 secound time window and not to prevent any kind of collision. The short range of the slow combined with the collision not being turned off forces you to use your only shield in a really controlled fashion, because you can still accidentally run into the enemy.
Saving your highest score and a Indikator are great ideas for additions.
Thank you NeptunianEclipse