The problem with seeds based on time in seconds is you only have a few dozen possible seeds, or a few thousand if you don't know when the game started. Make the seed based on more things, like milliseconds, process id, and hostname of the computer.
The second problem is you can't use just any random number generator, you need a crypto-safe one. For example, the "Mersenne Twister" random number generator used by python's random() is fast but it is not crypto-safe. If you can observe a sequence of 1000 or so random numbers, that's enough to predict all the future ones. But there are better random number generators like stream ciphers that you can use if predicting the PRNG is a problem.
The second problem is you can't use just any random number generator, you need a crypto-safe one. For example, the "Mersenne Twister" random number generator used by python's random() is fast but it is not crypto-safe. If you can observe a sequence of 1000 or so random numbers, that's enough to predict all the future ones. But there are better random number generators like stream ciphers that you can use if predicting the PRNG is a problem.